1. Field of Invention
The present invention relates to a protective film and a method for manufacturing the same. More particularly, the present invention relates to a semi-cured protective film and a method for manufacturing the same.
2. Description of Related Art
With the advance of electronic technologies, the designing trend demands compact and slim electronic devices which are easily portable. Accordingly, portable consumer electronics, for example, laptops, portable TVs, cell phones, personal digital assistants (PDAs) and multimedia players such as MPEG audio layer 3 players are getting smaller and lighter.
The casing of a portable electronic device provides direct protection for the device but also affects the cooling effect, weight, and aesthetic thereof. Common casing materials for the portable electronic device include metallic materials such as aluminum-magnesium alloy and titanium alloy, or plastic materials such as carbon fiber, polycarbonate (PC) and ABS engineering plastic. Casings made of different materials have their own advantages and shortcomings. No matter what material is used as the casing of a portable electronic device, a protective layer will be formed over the outer surface of the casing so as to prevent the surface from being scratched. FIGS. 1(a) and 1(b) illustrate the known method for forming a protective layer over the casing. In FIGS. 1(a) and 1(b), a protective layer 14 is spray coated over the casing 12 by one or more spray coating processes, then, the protective layer 14 is fixed onto the surface of the casing 12 by a baking process 18. The quality of the protective films formed by the spray coating process 16 and the baking process 18 depends largely on the skill of the operator, the apparatus used for spray coating and baking, and the cleanness of the environment for spray coating and baking. The aforementioned factors render the fraction defective of the products too high and therefore the cost of the final products stays high.
Another known technique to prevent the surface of the portable electronic device from scratching is to overlay a protective film thereon. Refer to FIG. 2. FIG. 2 is a schematic cross-sectional view illustrating the known protective film. As shown in FIG. 2, a protective film 20 comprises a substrate 22, a protective layer 24, and an adhesive 26. In order to obtain a protective film 20 with protection ability, the protective layer 24 is spray coated over one side of the substrate 22, and the adhesive 26 is spray coated over the other side of the substrate 22 so that a protective film 20 with protection ability could be obtained. Still refer to FIG. 2, in the known technique, the protective film 20 is overlaid onto an acceptor 28 thereby forming a formed article 30. In this case, a substrate with a protective layer is overlaid onto the acceptor 28, and since the substrate is not removed, the protective layer formed is thicker. Furthermore, if the surface of an acceptor is curved or angled and not completely flat, to form an applicable protective film with better formability has to compromise the hardness of the protective layer. However, although a protective layer with lower hardness is easy to apply, it might decrease the protection ability of the protective film. On the other hand, while a protective layer with higher hardness might provide better protection, it is usually brittle and with lower formability during the manufacturing process. In addition, when the acceptor has a special angle, the protective film might exhibit defects such as whitening at the angle or poor adhesion with the casing. Therefore, although known protective films are easy to apply, their operability in later processing is extremely limited.
In view of the foregoing, it is desired to provide an easy-to-apply protective layer with a better yield and protective effect.